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Major Land Resource Area or ecological site by name and/or ID.
General information
Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
MLRA notes
Major Land Resource Area (MLRA): 022A–Sierra Nevada and Tehachapi Mountains
MLRA 22A
Major Land Resource Area 22A, Sierra Nevada Mountains, is located predominantly in California and a small section of western Nevada. The area lies completely within the Sierra Nevada Section of the Cascade-Sierra Mountains Province. The Sierra Nevada range has s gentle western slope, and a very abrupt eastern slope. The Sierra Nevada consists of hilly to steep mountains and occasional flatter mountain valleys. Elevation ranges between 1,500 and 9,000 ft throughout most of the range, but peaks often exceed 12,000 ft. The highest point in the continental US occurs in this MLRA (Mount Whitney, 14,494 ft). Most of the Sierra Nevada is dominated by granitic rock of the Mesozoic age, known as the Sierra Nevada Batholith. The northern half is flanked on the west by a metamorphic belt, which consists of highly metamorphosed sedimentary and volcanic rocks. Additionally, glacial activity of the Pleistocene has played a major role in shaping Sierra Nevada features, including cirques, arĂȘtes, and glacial deposits and moraines. Average annual precipitation ranges from 20 to 80 inches in most of the area, with increases along elevational and south-north gradients. Soil temperature regime ranges from mesic, frigid, and cryic. Due to the extreme elevational range found within this MLRA, Land Resource Units (LRUs) were designated to group the MLRA into similar land units.
LRU XI Central Sierra Lower Montane
This LRU comprises the lower elevations of the western, central, Sierra Nevada Mountains. Elevations are typically between 2,000 and 4,700 feet, with higher elevations in the south. The frost free season ranges from 150 to 240 days, MAAT ranges from 50 to 62 degrees F, and MAP ranges from 32 to 57 inches. Soil temperature regime is generally mesic, although warmer pockets of thermic exist within this LRU.
Ecological site concept
This site is distinguished by other ecological sites by virtue of occurring on deeper pockets within the Mehrten (and other) volcanic formations. Occurs on slopes generally greater than 25%. Annual precipitation ranges between 39 and 49 inches per year, with much occurring between November and May in the form of snow.
Vegetation includes canyon live oak, manzanita and other chaparral shrubs. Often on the steeper areas there are bands of stunted conifers to include ponderosa pine and incense cedar.Table 1. Dominant plant species
Tree (1) Quercus chrysolepis
(2) Calocedrus decurrensShrub (1) Adenostoma fasciculatum
(2) Arctostaphylos manzanitaHerbaceous Not specified